The present invention relates to an improved, play-free precision drive apparatus.
In order to make a drive apparatus high precision, bearings that have substantially no play are required to carry the drive element. For this purpose, it is a known practice to mount the drive element on axially or radially biased roller bearings, such as conical roller bearings, shoulder bearings, or "ball guides" (Kugelfuhrungen). Such biased bearings however have the disadvantage that they are relatively difficult to rotate because the relatively high drag generated by the bias tension, which is often applied to all of the roller, or ball, elements of the bearing. In addition, biased bearings generally do not permit high speeds of rotation, they are relatively difficult to adjust, and they are relatively easily damaged.
It is also known to utilize aerostatic or hydrostatic bearings in such play-free drives, but their use is complicated by the fact that they require fluid pumps such as air or oil pumps for their operation.